package com.qingguo.MapReduce;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import java.io.IOException;

public class Com_avg_stay {
    //    第一步写MYmap类并继承Maper
    public static class Mymap extends Mapper<LongWritable, Text, Text, LongWritable> {
        //重写map方法
        @Override
        protected void map(LongWritable k1, Text v1, Context context)
                throws IOException, InterruptedException {
            //将进来的值切分
            String[] split = v1.toString().split("\t");
            if(split.length==8&&!(split[4].equals("\\N"))) {
                String local = split[2];
                long ms = Long.parseLong(split[4]);
                context.write(new Text(local), new LongWritable(ms));
            }
        }
    }

    //*********************************************************************************************
    //第二步写Myreduce并继承Reducer类
    public static class Myreduce extends Reducer<Text, LongWritable, Text, LongWritable> {
        //重写reduce方法
        @Override
        protected void reduce(Text k2, Iterable<LongWritable> v2s, Context context)
                throws IOException, InterruptedException {
            long sum = 0;
            long count = 0;
            for (LongWritable longWritable : v2s) {
                sum = sum + longWritable.get();
                count++;
            }
            long avg = sum / count;
            context.write(k2, new LongWritable(avg));
        }
    }

    //*****************************************************************************
//第三步，编写程序主入口，组装mapreduce
    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
//加载hadoop的配置参数
        Configuration conf = new Configuration();
//创建任务的对象(单例设计模式)传入配置参数，并取名字
        Job job = Job.getInstance(conf, Com_avg_stay.class.getName());
//设置打包的类
        job.setJarByClass(Com_avg_stay.class);
//设置读取文件的hdfs路径
        FileInputFormat.addInputPath(job, new Path(args[0]));
//指定需要执行的map类
        job.setMapperClass(Mymap.class);
//指定map输出的序列化类型
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(LongWritable.class);
        //执行Combiner
        job.setCombinerClass(Myreduce.class);
//指定需要执行的reduce类
        job.setReducerClass(Myreduce.class);
//指定reduce的序列化类
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(LongWritable.class);
//指定输出的hdfs路径
        FileOutputFormat.setOutputPath(job, new Path(args[1]));
//提交任务，等待执行完成，并打印执行日志
        job.waitForCompletion(true);
    }

}

